import logging
def cal_mul(exp):
    exp=4*6
    logging.debug('4*6=24')
    return 24



def cal_div():
    pass


def cal_add():
    pass


def cal_sub(exp):
    exp=3-24
    logging.debug('3-24=21')
    return 21



def cal_inner_bracket(exp2):
    exp2=3-4*6
    ret=cal_mul(4*6)
    exp2=3-24
    ret=cal_sub(3-24)
    logging.debug('3-4*6=-21')
    return -21


def main(exp):
    exp=(1+2*(3-4*6))/5   #要去括号
    ret=cal_inner_bracket(3-4*6)
    return ret

logging.basicConfig(level=logging.DEBUG)
ret=main('(1+2*(3-4*6))/5')
print(ret)